The present invention relates to manufacturing machines, and more particularly to machines such as automatic assembly machines in which a workpiece and suitable tooling are automatically manipulated relative to each other to assemble parts into the workpiece or otherwise advance the manufacturing process of the workpiece.
A number of forms of machines such as automatic assembly machines have been proposed and actually put into use in the prior art. One of the principal applications of such machines has been the automatic manipulation of parts and tools to assemble relatively complex assemblies out of simpler parts or components. In such machines, one or more stations are provided, with a parts feeder or the like provided at each work station which supplies the parts to be added to the workpiece at the work station and a conveyor system interconnecting the work stations to transport the workpiece from work station to work station, with the workpiece becoming progressively more completely assembled at each work station.
At the work station, means are provided to position and hold the workpiece rigidly in place at the work station while suitable tooling at the work station manipulates the parts of components supplied to the work station by the part feeder to assemble these parts into the workpiece, thereby advancing the assembly of the workpiece. After the work station had completed its portion of work on the workpiece, the workpiece is advanced by the conveyor system to the next work station, where another assembly operation is effected on the workpiece.
Obviously, if accurate assembly of the workpiece with low tolerance is to be effected by the work station, the workpiece must be accurately positioned while it is being held at the work station during the assembly operation. In the prior art, this has usually been achieved by, in effect, the assembly machine being one large, monolithic structure, with the conveyor and all work stations being rigidly and accurately coupled to each other, usually by being secured to a common heavy metal base plate in which the mounting holes for the conveyor and the work station have been accurately machined, in order to permit accurate work by the work stations on the workpiece.
Such machines as have existed in the prior art have been of highly specialized design to perform the particular automatic assembly function on a particular type of workpiece. The biggest items and the cost of such machines has been for special engineering, fabrication and debugging, with only a relatively small portion of the cost being for standard modules. Some manufacturers have claimed the virtue of modularization for their machines, but such modules have usually consisted only of limited portions of the machine, such as conveyors and actuator drive chassis and special purpose mechanisms such as complex but limited pick and place assemblies.
Because of these above-mentioned limitations in the prior art, such automatic assembly machines have been of only limited utility, since their high cost can be justified only in manufacturing operations which produce large quantities of parts, such as at least several million parts per year of the same type. Because of this limitation, most such machines have been found in the automobile industry, which is one of the few manufacturing and assembly operations which require such large numbers of parts.